My long sought after solution to the glass problem may be dependent on the modeling software I use, but just in case other software has the same capability I will try to explain with out illustrations...
Step 1. Create and complete the model with out glass in the window openings
Step 2. When model is complete then place the glass (this will be a surface) into the model window openings
Note: the degree of glass translucent is set in the texture file for the model.
Step 3. Select each window surface (Shift click) and make these surfaces a group and then make note of the xyz coordinates of the glass group.
Step 4. Select the glass group and slide it out of the model far enough to allow you to select just the building with out the glass.
Step 5. Select just the building and merge the model objects into one object. For me this is a "merge command"
Step 6. After the "merge process" on the building" next slide window group back into their original xyz location
Step 7. Save the model as an "x" file... DONE
It appears (in my case) this incorporates the glass into the "x" file as a separate last object which it seems GG requires.
Note: the "FPE" file requires the inclusion of "transparency =2"
That's the way I do it... but none of this may apply to users of other modeling software.
In the long run (and I mean LONG) I agree that Lee should come up with a more universal solution for translucent glass. It should be a more inherent part of GG with out the user fussing around.
Windows 10 creator,64 bit| Intel i7-7700 @3.60GHZ Quad|CPU PASSMARK 10,794|Memory 16GB |NVIDIA GEFORCE GTX 1070|GPU PASSMARK 11,071